Apparatus for the preparation of elliptical structures



F.'J. LOWES 3,376,602

. APPARATUS FOR THE PREPARATION OF ELLIPTICAL STRUCTURES April 9, 1968 Filed July 14, 1967 I 2 Sheets-Sheet 1.

INVENTOR. Free J. L owe;

F. J. LOWES A ril 9, 1968 APPARATUS FOR THE PREPARATION OF ELLIPTICAL STRUCTURES 2 Sheets-Sheet 2 Filed July 14, 1967 illIlTW IULLI I! I i INVENTOR.

Fr d J. Lowe's %/Q9Q -2M I HGENT Unite States Patent 3,376,602 APPARATUS FOR THE PREPARATION OF ELLIPTICAL STRUCTURES Fred J. Lewes, Midland, Mich, assignor to The Dow Chemical Company, Itdidland, MiclL, a corporation of Delaware Filed July 14, 1267, Ser. No. 653,485 Claims. (Cl. 18-5) ABSTRACT OF THE DISCLDSURE An apparatus is described which is suitable for spiral deposition of building materials to form a generally ellipsoidal structure, the ellipsoidal configuration being generated by a three dimensional variation of the string and pencil method. A mechanism is provided which present fouling of the string.

This invention relates to an apparatus for the preparation of generally elliptical structures, and more particularly relates to an apparatus for the preparation of elliptical structures by the successive deposition of portions of a building material in a generally spiral pattern.

Various shapes and forms of walled structures are prepared in accordance with the teaching of U8. Letters Patent 3,206,899. Many of these structures are generally circular in configuration and oftentimes offer less than the desired configuration. Frequently, it is desirable to prepare walled structures similar to those set forth in US. Patent 3,206,899 but having a hemiellipsoidal configuration. Such a configuration is oftentimes more desirable for many applications than circular or spheroidal structures. By the term ellipsoidal surface is meant a surface which generally conforms to the configuration of an ellipsoid or to any portion of such a surface. It has been proposed to prepare generally ellipsoidal structures employing a material depositing head supported on a telescoping boom. The length of the boom and position of the head are controlled by a cable or similar flexible element. In essence, the apparatus employed utilizes a three dimensional version of the string and pencil method of generating an ellipse. The pencil is replaced by an arm or pivoted boom, pivoted generally on the major axis and mid-Way between the foci of the ellipse or ellipsoidal figure to be generated. The position of the material depositing head is controlled by a cable anchored at the foci of the ellipsoid. Connection of the cable to the material depositing head presents significant problems involving bearings and rotation of the boom or arm member. The boom swings readily in a plane containing the foci and normal to a plane upon which the structure is being constructed. However, as the boom is rotated, irregularities oftentimes arise due to the requirement that the cable in effect rotate about the arm or boom.

It would be desirable if there were available an improved apparatus which would permit the deposition of the building material in a generally hemiellipsoidal configuration.

It would also be beneficial if such an apparatus were capable of generating ellipsoidal structures of varying proportions.

It would be highly desirable if such an apparatus were relatively light and simple to transport.

It would be highly desirable if an improved apparatus were available which would permit smooth movement of a boom or elongate member supporting a material de positing head in an apparatus for the generation of generally ellipsoidal structures.

These benefits and other advantages in accordance with the present invention are achieved in an apparatus for the construction of walled structures by a spiral generation technique wherein a strip of building material is deposited in a generally helical configuration to form a walled structure, the apparatus comprising in cooperative combination a base, the base having a support engaging surface and an oppositely disposed pivot surface, the pivot surface having supported thereon a pivot adapted to permit rotation of a member about the pivot in a generally hemispherical solid angle, an elongate member having a first end and a second end, the first end of the elongate member attached to the pivot and adapted to pivot within the solid angle, the elongate member having aflixed to the second end a material depositing head adapted to deposit a material of construction in the form of an elongate strip, a flexible element restraining means pivotally affixed to the material depositing head, the flexible element restraining means passing through a guide and bearing means slidably supported by the second end of the elongate member, the guide and bearing means being in fixed angular relationship relative to a radius of the elongate member, the material depositing head being adapted to rotate about the axis of the elongated element, the guide and bearing means being intermediate the first end of the elongate element and the flexible element restraining means, means to vary the spacing between the foam depositing head and the first end of the elongate element, a flexible element passing through the flexible element restraining means and sliding therein, the flexibile element having a first end and a second end, the first and second ends of the flexible element secured in spaced relationship to the pivot end and in a plane adjacent to the pivot and generally equally spaced therefrom.

Further features and advantages of the present invention will become more apparentfrom the following specification when taken in connection with the drawing wherein:

FIGURE 1 is a schematic representation of an apparatoe in accordance with the present invention.

FIGURE 2 is a schematic representation of the attachment of the material depositing head of FIGURE 1 to the elongate member or boom of FIGURE 1.

FIGURE 3 schematically depicts motion of the foam depositing head of FIGURE 1.

FIGURES 4, 5, 6 and 7 depict means of pivotally aflixing the elongate element of FIGURE 1 to the base.

In FIGURE 1 there is schematically represented an apparatus in accordance with the present invention generally designated by the reference numeral 10. The apparatus 10 comprises in cooperative combination a base member 11. The base member 11 has a support engaging surface 12. Oppositely disposed from the support engaging surface 12 is a pivot surface 13 having aflixed thereto a pivot 14. An elongate element 16 having a first end 17 and a second end 19 is afiixed to the pivot 14 at the first end 17. The elongate element can pivot within a solid angle and is generally restricted in motion by the base 11. The pivot 14 is so constructed and arranged so as to permit motion in a solid angle without permitting angular rotation of a radius of the elongate element relative to the base 11, that is, as the elongate element 16 is rotated in a solid angle about the base 11 the elongate element 16 is restrained from rotating about its own axis. The elongate element 16 comprises a first portion 21 and a second portion 22. The portion 22 telescopes within the portion 21 and the portions are urged apart by means of an internal tensioning means or spring 25. Aflixed to the first portion 21 of the elongate element 16 is a flexible element guide and restraining means 27. A flexible element 29 of fixed length passes through the flexible element restraining means. The flexible element 29 has a first end 30 and a second end 31. The first and second ends and 31 are afiixed to a base or support 33. The ends 30 and 31 are generally equally spaced from the pivot 14 and are disposed generally on a common line. A foam or material depositing head 35 is aflixed to the second end 13 of the elongate element 16 and maintained in fixed spaced relationship from the flexible element restraining means. The depositing head 35 is ada ted to pivot about the elongate element 16 on a bearing 37.A portion 38 of generally hemielliptical structure composed of a plurality of strips is shown in operative engagement with the depositing head 35.

In FIGURE 2 there is schematically depicted a view of the guide and restraining means 27 employed in the apparatus of FIGURE 1. The guide and restraining means 27 comprises a pulley or sheave 41. Disposed within the first portion 21 of the elongate element 16, the sheave or pulley 41 is in operative engagement with the flexible element 29 and is rotatably supported by a frame 43 affixed to the material depositing head 35 by a swivel or pivot 42 which permits rotation of the head 35 with respect to the longitudinal axis of the element 16. The material depositing head 35 is shown in operative engagement with the portion 38 of the ellipsoidal structure. The portion 21 defines a slot or cavity 44 which permits positioning of the head 35 along the major axis of the elongate element 16. Advantageously, the depositing head 35 may be supported upon a one-piece elongate element and by a suitable tensioning means, such as spring, hydraulic or pneumatic cylinder, the telescoping feature shown in FIGURE 1 may be eliminated. Generally, the telescoping feature is desirable for maximum versatility.

In FIGURE 3 there is schematically represented an ellipsoidal path traced by an apparatus in accordance with the invention. One ellipsoidal path is represented by the reference numeral 55. The reference numeral 56 represents the second end of the elongate member such as the elongates member 16. The reference numeral 57 indicates the pivot point whereas the flexible restraining element is depicted by the reference numeral 58. The depositing head 56 is free to move to any position about the ellipse when it is positioned adjacent the plane of the paper or ground support. As the head is raised by the deposition of build ing material, the size of the ellipse decreases as the distance from a plane of the support increases, resulting in an ellipsoidal structure.

In FIGURE 4 there is schematically represented a fractional view of a suitable pivot means 14a shown in operative combination with an elongate element 16a having a second portion 22a and supported by a base member 11a having a support engaging surface 12a. The pivot means 14a comprises a plurality of high tensile elements in generally parallel relationship formed into a flexible wire cable such as a braided cable. The cable acts as a universal joint and generally prevents rotation of the boom about its axis relative to the base 11a.

In FIGURE 5 there is depicted an alternate pivot means 14b aflixed to an alternate element 16b and a base member 11b. The pivot 14b beneficially is a universal joint preferably of the constant speed variety well known in the art.

In FIGURE 6, an alternate pivot 14c is affixed to an elongate member 16c and a base 110. The pivot 140 comprises a support 60 rigidly aflixed to the base 110 and extending generally normal thereto. Remote from the base 110, the support member 60 terminates in a ball and socket joint 61 having a socket 62 and a ball 63. The ball and socket joint 61 is also aflixed to the elongate element 63. A crown gear 65 is slidably carried by the support 60 and keyed thereto to prevent rotation of the crown gear. The crown gear is in operative combination with a resilient tensioning means or spring 67 which tensions the crown gear toward the ball and socket joint 61. A spur gear 68 is rigidly afiixed to the elongate element 63 adjacent the ball and socket joint 61 and is of sufficient length to engage the crown gear 65. It is essential and critical that the gearing ratio of the spur gear to the crown gear be 1:1 and that the dimensions of the spur gear (not shown in proportion in the drawing) be such that the crown and spur gears are engaged as the elongate element 16c is rotated.

In FIGURE 7 there is schematically depicted an alternate pivot arrangement designated as 14d. The pivot 14d comprises a generally cylindrical c p like housing 70 having a first end 71 aflixed to the base 11d. The housing 71 defines an upper or open end 72 having rigidly afiixed thereto a flexible diaphragm 73 of generally discoidal configuration having a plurality of annular corrugations 74 therein. An elongate element 16d is aflixed to i a central portion of the diaphragm 73 in such a manner that no relative axial rotation of the elongate element 16d, the diaphragm or the housing is permitted.

By employing an extensible boom or elongate member such as the member 16 of FIGURE 1, a foam depositing head is caused to follow an elliptical path as the effective distance between the fiexible element restraining means and the pivot can vary within the desired mechanical limits. The foam depositing head being disposed adjacent the flexible element restraining means follows a path or traces a surface which is very close to hemiellipsoidal.

Employing the apparatus substantially as depictedin FIGURES 1 and 2, a wide variety of generally elliptical structures are readily preparedfrom foam plastic, conconcrete and the like.

As is apparent from the foregoing specification, the present invention is susceptible of being embodied .with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understoodthat all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set.

forth and defined in the hereto-appended claims.

What is claimed is:

1. An apparatus for the construction of walled structures by a spiral generation technique wherein a strip of building material is deposited in a generally helical configuration to form a walled structure, the apparatus comprising in cooperative combination a base, the base having a support engaging surface and an oppositely disposed pivot surface, the pivot surface having supported thereon a pivot adapted to permit rotation of a member about the pivot in a generally hemispherical solid angle,

an elongate member having a first end and a second end, the first end of the elongate member attached to the pivot and adapted to pivot within the solid angle, the elongate member having aflixedto the second end a material depositing head adapted to deposit a material of construction in the form of an elongate strip,

a flexible element restraining means pivotally affixed to the material depositing head, the flexible element restraining means passing through a guide and bearing means slidably supported by the second end of the elongate member, the guide and bearing means being in fixed angular relationship relative to a radius of the elongate member, the material depositing head being adapted to rotate about the axis of the elongate element, the guide and bearing means being intermediate the first end of the elongate element and the flexible element restraining means,

means to vary the spacing between the foam depositing head and the first end of the elongate element,

a flexible element passing through the flexible element restraining means and sliding therein, the flexible element having a first end and a second end, the first and second ends of the flexible element secured in spaced relationship to the pivot end and in a plane adjacent to the pivot and generally equally spaced therefrom.

2. The apparatus of claim 1 wherein the elongate element comprises first and second portions, one telescoping within the other, and means to urge the first and second portions apart.

3. The apparatus of claim 1 wherein the material depositing head is slidably secured to the elongate element.

4. The apparatus of claim 3 including means to resiliently urge the material depositing head toward the second end of the elongate element.

5. The apparatus of claim 1 wherein the first and second ends of the flexible element and pivot are disposed generally on a line.

6. The apparatus of claim 1 wherein the material depositing head is adapted to deposit a synthetic resinous foam.

7. The apparatus of claim 1 wherein the pivot comprises a flexible cable.

8. The apparatus of claim 1 wherein the pivot comprises a universal joint.

9. The apparatus of claim 1 wherein the pivot comprises a ball and socket joint and relative axial rotation of the boom is prevented by means of spur and crown gears, one gear mounted to the boom, one gear afi'ixed to the base, and the gearing ratio between the crown and spur gears is 1: 1. I

10. The apparatus of claim 1 wherein the pivot means comprises a flexible diaphragm rigidly afiixed to both the elongate element and the base.

References Cited UNITED STATES PATENTS 2,339,892 1/1944 Urschel. 2,877,530 3/1959 Winn. 2,979,798 4/ 1961 Price.

WILLIAM J. STEPHENSON, Primary Examiner. 

